I'm just checking out the game before buying it, since you are so kind as to provide the ability to download it first. I'm only about 5-10 minutes into it, and I am experiencing a kind of game breaking bug.
On entering the settings menu, there is no way to exit back to the game. There is no visible "exit", "ok" or similar button, and the Android "back" button also does nothing.
I am using a Motorola e5, with Android 8.0.0, if that helps.
Obviously you may have other things on your plate than one person's bug, but I figured it was better to tell you than to just toss or the game without trying a bit more to play it.